Conventionally, there are known sheet finishing apparatuses set on downstream sides of image forming apparatuses such as a copying machine, a printer, and a multi-functional peripheral (MFP) and configured to apply finishing such as folding and saddle stapling to printed sheets.
Among these sheet finishing apparatuses, some sheet finishing apparatuses perform not only saddle folding for folding sheets in the center but also triple folding such as so-called Z-folding, inward triple folding, and outward triple folding. However, the sheet finishing apparatus or a sheet folding apparatus in the past configured to perform the triple folding includes exclusive folding mechanisms such as a folding roller, a conveying path, and a conveying roller exclusively used for the triple folding.
Therefore, there is a demand for a sheet folding apparatus and a sheet finishing apparatus that can perform the saddle folding (double folding) and the triple folding with a simpler and more compact configuration.